This proposal is divided into two sections: Section I, to be performed in the experimental laboratory; and Section II, a clinical section. In the experimental laboratories, eleven projects (Projects A-K) will be pursued, the aim of which is to examine several new promising approaches to reduce infarct size, to evaluate new methods to determine changes in the size of myocardial injury, and to gain a more precise understanding of the functional and anatomic conditions of the salvaged myocardium. Section II involves the studies of patients with acute myocardial infarction. As in the case of the laboratory studies, it is planned to analyzed the effect of the most promising interventions to reduce myocardial injury in patients and at the same time to assess new methods of measuring infarct size and its changes.